The Synthesis, Structures And Properties Of Complexes Containing Bipheny-2,2',6,6'-Tetracarboxylic Acid Ligand

In recent years, the design and synthesis of new materials "on demand" is becoming increasingly important. In the field of supramolecular chemistry and crystal engineering, the design and assembly of metal-organic coordination frameworks (MOFs) with appealing structures and properties have stimulated interests of chemists. As far as we know, the formation of MOFs is influenced many factors, such as metal ions, organic ligands, counterions, solvent molecules and Ph of the reaction mixture, etc. Among these factors, the selection of organic ligands is one of the most important aspects. The configuration, rigidity, substituent and coordination modes of organic ligands have an important effect on the final structures.Thus, among various organic ligands, multicarboxylate ligands are selected as multifunctional organic ligands, not only because of their various coordination modes to metal ions, resulting from completely or partially deprotonated sites allowing for the large diversity of topologies, but also because of their ability to act as H-bond acceptors and donors to assemble supramolecular structures. In this paper, we select bipheny-2,2',6,6'-tetracarboxylic acid (H4bta).In recent years, people have been considerable interested in unsymmetrical Schiff base complexes because they have significant antiviral and antibacterial activities. In particular, their specific structures and properties have attracted much more interest. In addition, the molecular-based magnetic materials have shown spectacular advances over the past two decades, in which the study of heterometallic binuclear complexes has played an important and leading role. A successful strategy in obtaining the desired spin topology is the "complex as ligand" method.In view of reasons above and from the standpoint of molecular design, we select Schiff base Cu(Ⅱ) mononuclear complex CuSaenAc and bipheny-2,2',6,6'-tetracarboxylic acid to get a new complex, then we use other multicarboxylate ligands and chiff base Cu(Ⅱ) mononuclear complex to get other two complexes.So, in this thesis, our work includes two parts as follow: 1. We selected bipheny-2,2',6,6'-tetracarboxylic acid (H4bta) as leading ligand, 2,2':6',2"-terpyridine(Terpy),1,10-phenanthroline(phen) 1,3-bis(imidazol-1-methylene)-benzene(m-bix) and 4,4'-bipyridine(bpy) as additional ligands to react respectively with copper,nickel,cobalt and cadmium salts by fine control over synthetic conditions gaining six complexes: [Cu2(Hbta)(Terpy)2(H2O)2]·(NO3)·2H2O (Ⅰ),[Cu(H2bta)(Terpy)] (Ⅱ) [Ni(H2bta)(Terpy)(H2O)]·3H2O (Ⅲ),[Cu (bta)0.5(phen)]·(H2O)2.25 (Ⅳ) [Co(bta)0.5(m-bix)2]·2H20 (Ⅴ) and [Cd(H3bta)2(bpy)] (Ⅵ) by hydrothermal method.Comparing withⅠandⅡ, we find that pH value has very important roles in the self-assembly. Reacting in different pH value, complexⅠexhibits a discrete structure, whereas complexⅡhas a 1-D neutral coordination chain.In the same experiment condition, we used different additional ligands to assemble with different metal salts. Then we obtained the later three complexes. X-ray diffraction structure reveals thatⅢandⅣhave different 1-D chain whileⅤandⅥexhibit 3-D coordination frameworks.2. We used Schiff base complex CuSaenAc to react respectively with bipheny-2,2',6,6'-tetracarboxylic acid (H4bta),2,2'-oxydibenzoic acid (H2odba) and phthalic acid (H2pa) by volatilization gaining three complexes: [(CuSaen)3(Hbta)(H2O)2]·4H2O (Ⅶ), [(CuSaen)2(odba)]·CH3OH (Ⅷ) and [(CuSaen)2(pa)]-2H2O (Ⅸ). ComplexⅦandⅧboth exhibits 0-D structure and complexⅨhas a 1-D chain structure.We attempted to use Schiff base complex CuSaenAc to react with bipheny-2,2',6,6'-tetracarboxylic acid by hydrothermal method gaining another complex [Cu2(bta)(en)2(H2O)2]·8H2O (Ⅹ). ComplexⅩhas a 2-D structure. However, C=N in the CuSaenAc was broken and ethylenediamine was only remained indicating CuSaenAc was not stable at high temperature.